• 한국정밀공학회지
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• 제15권7호
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• pp.85-90
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• 1998

The business of manufacturing is increasingly becoming time-compressing, precise and long-life oriented, owing to various needs from the consumers and harsh global competition. With the emergence of the layer laminate manufacturing method, it is possible to produce prototypes directly from 3D CAD and additive process, the production time and cost have shortened dramatically. However there are some problems like surface-step, dimensional deviation and warp. A newly developed powder casting is suitable for rapid-manufacturing metallic tools. Powder casting can serve as a promising rapid tooling method because of high density characteristics and low dimensional shrinkage below 0.1％ during sintering and infiltration. By this process, we have realized significant time savings bypassing the wait for prototype tooling and cost savings eliminating the expense of conventional prototype tooling process.

• 한국세라믹학회:학술대회논문집
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• 한국세라믹학회 2000년도 추계총회,초청강연,특별강연,연구발표회
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• pp.100.2-100
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• 2000

• 한국물환경학회지
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• 제34권1호
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• pp.57-66
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• 2018

Water disasters such as flash floods and inundation caused by localized heavy rainfall in urban areas have a large impact on climate change but are also closely related to the increase in impervious areas as pointed out in domestic and international studies. It is difficult to secure natural green areas in urban areas that have already been developed. So, urban regeneration can be expected using water management optimized with technologies to secure infiltration and storage capacity such as Low-Impact Development technology. In this study, the water cycle improvement ability was confirmed by applying the LID technology within the district unit plan of the environmentally friendly village, and the economic feasibility of LID application was analyzed by estimating the costs and benefits of installing the facilities. The site was planned to conserve sufficient green and plans for securing the watershed infiltration and storage capacity were formulated with the application of additional LID technology, such as infiltration trenches, rain barrels and permeable pavements. The LID design method applicable to the site was established, and the water balance of the watershed was analyzed through simulations of the SWMM model. The water circulation improvement effect was confirmed through the water balance analysis, and the cost-benefits were determined according to the estimation method, and the economic analysis was conducted. This study confirms that the investment of LID technology is economically feasible for the hydrological improvement effect of the housing complex.

• 센서학회지
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• 제24권6호
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• pp.385-391
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• 2015

In this paper, we propose a new method to infiltrate $Fe_3O_4$-nanoparticles into a porous silicon film and a monitoring technique to detect packing density of nanoparticles within the film. Recently, research to use porous silicon as a drug carrier or a new functional sensor material by infiltrating $Fe_3O_4$-nanoparticles has been extensively performed. However, it is still necessary to enhance the packing density and to develop a monitoring technique to detect the packing density in real time. In this light, we forcibly injected a nanoparticle solution into a rugate-structured free-standing porous silicon (FPS) film by applying a pressure difference between the two sides of the film. We found that the packing density by the pressure-infiltration method proposed in this paper is enhanced, relative to that by the previous diffusion method. Moreover, a continuous shift in wavelength of the rugate reflectance peak measured from the film surface was observed while the nanoparticle solution was being injected. By exploiting this phenomenon, we could qualitatively monitor the packing density of $Fe_3O_4$-nanoparticles within the FPS film with the injection volume of the nanoparticle solution.

• Geomechanics and Engineering
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• 제22권3호
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• pp.207-217
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• 2020

Slope reliability analysis and risk assessment for spatially variable soils under rainfall infiltration are important subjects but they have not been well addressed. This lack of study may in part be due to the multiple and diverse evaluation indexes and the low computational efficiency of Monte-Carlo simulations. To remedy this, this paper proposes a highly efficient computational method for investigating random field problems for slopes. First, the probability density evolution method (PDEM) is introduced. This method has high computational efficiency and does not need the tens of thousands of numerical simulation samples required by other methods. Second, the influence of rainfall on slope reliability is investigated, where the reliability is calculated from based on the safety factor curves during the rainfall. Finally, the uncertainty of the sliding mass for the slope random field problem is analyzed. Slope failure consequences are considered to be directly correlated with the sliding mass. Calculations showed that the mass that slides is smaller than the potential sliding mass (shallow surface sliding in rainfall). Sliding mass-based risk assessment is both needed and feasible for engineered slope design. The efficient PDEM is recommended for problems requiring lengthy calculations such as random field problems coupled with rainfall infiltration.

• 대한간호학회지
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• 제34권6호
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• pp.924-933
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• 2004

Purpose: This study was to examine the effects of hand massage and hand holding as nursing interventions on the anxiety in patients with local infiltration anesthesia. Method: The design of this study was a nonequivalent, control group, non- synchronized design. The subjects of this study consisted of 15 patients for the hand massage group, 15 patients for the hand holding group and 17 patients for the control group awaiting surgery in the operation room of a general hospitalin Daegu. As an experimental treatment, hand massage was carried out by the Hand Massage Protocol developed by Snyder(1995) and interpreted by Cho(1998) and hand holding developed by Cho(1998). The data were analyzed by SPSS/WIN, T-test, ANOVA, Cronbach's a, and the Scheffe test. Results: The hand massage group and hand holding group were more effective than the control group in reducing anxiety, VAS score, systolic blood pressure and pulse rate. Conclusion: Hand massage and hand holding are effective nursing interventions that alleviates the psychological and physiological anxiety of patients with local infiltration anesthesia. In particular, the simple contact of hand holding is regarded as an effective and easily accessible nursing intervention in the operating room.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2015년도 제49회 하계 정기학술대회 초록집
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• pp.190.1-190.1
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• 2015

Graphite has excellent mechanical and physical properties. It is known to advanced materials and is used to materials for molds, thermal treatment of furnace, sinter of diamond and cemented carbide tool etc. SiC materials are coated on the surface and holes of graphite to protect particles emitted from porous graphite with 5%~20% porosity and make graphite hard surface. SiC materials have high durability and thermal stability. Thermal CVD method is widely used to manufacture SiC thin films but high cost of machine investment and production are required. SiC thin films manufactured by Si reaction liquid and vapore with carbon are effective because of low cost of machine and production. SiC thin films made by vapor silicon infiltration into porous graphite can be obtained for shorter time than liquid silicon. Si materials are evaporated to the graphite surface in about $10^{-2}$ torr and high temperature. Si materials are melted in $1410^{\circ}C$. Si vapor is infiltrated into the surface hole of porous graphite and $Si_xC_y$ compound is made. $Si_x$ component is proportional to the Si vapor concentration. Si diffusion coefficient is estimated from quadratic equation obtained by Fick's second law. The steady stae is assumed. Si concentration variation for the depth from graphite surface is fitted to quadratic equation. Diffusion coefficient of Si vapor is estimated at about $10^{-8}cm^2s^{-1}$.

• 한국조경학회지
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• 제34권4호
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• pp.116-128
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• 2006

This study focuses on hydrological changes caused by developments in the 13th, 14th (Motjarigol) district in Eun Pyoung New Town, Seoul on the basis of the Land Use Planning of development plan. Through analyses from the hydrological experiments about rainfall outflow using universal equation and amounts of infiltration through soils, the changes in amounts of overflows were estimated and the results were discussed from a urban ecological point of view. As a result, it has been predicted that the amount of rainfall outflow at post-development was dramatically increased, compared to pre-development. Installing of Derbris Dams and infiltration facilities were suggested as alternative plan to meditigate these changes. If we apply these alternatives, the rainfall outflow would be reduced up to 30% compared to the development plan without BMPs (Best Management Practice). In conclusion, it is proposed that once the ecological principles were considered during development planning process, we can minimize the adverse effects of developments to our environments.

• 한국농공학회지
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• 제35권3호
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• pp.36-46
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• 1993

The purposes of this study are to develop three-layered Green-Ampt infiltration model considering temporal variation of physical properties of soil and to evaluate the model with field experiment on bare-tilled and soybean-growing soil plots under natural rainfalls. Infiltration tests were conducted on a sandy loam soil. The model has three-layered soil profile including a surface crust, a tilled layer, a subsoil and considers temporal variation of porosity, hydraulic conductivity, capillary pressure head on a tilled layer by natural rainfalls and canopy density variation of crop. Field measurement of porosity, average hydraulic conductivity and average capillary presure head on a tilled layer were conducted by soil sampler and air-entry permeameter at regular intervals-after tillage. It was found that temporal variation of porosity and average hydraulic conductivity might be expressed as a function of cumulative rainfall energy and average capillary pressure head might be expressed as a function of porosity of a tilled soil. The model was calibrated by an optimization technique, Hooke and Jeeves method using hourly surface runoff data. With the calibrated parameters, the model was verified satisfactorily.

• 대한토목학회논문집
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• 제31권2B호
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• pp.99-108
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• 2011

본 연구에서는 개발이전의 도시하천 유황을 복원시키기 위한 유수지 및 침투기반 저류지의 복합설계기법이 적용된다. 적용된 기법은 NRCS-CN 강우유출수 산정기법을 근간으로 하고 있으며, 이로부터 침투기반 저류지 및 유수지의 크기가 온천천 유역을 대상으로 결정된다. 이 때, 강우유출수 관리시설을 설계하기 위한 대상지역은 온천천 유역 중 해발 70 m 이하의 도시화 지역으로 제한하였다. 적용 결과 제안된 기법은 온천천 유역의 개발 이전의 유황을 재현하는데 유용하게 적용될 수 있을 것으로 기대된다.